The present invention relates to a new and improved structure of a monolithic integrated semiconductor device. The present invention also relates to a new and improved method of manufacturing such monolithic integrated semiconductor devices.
During the manufacture of customer specified integrated circuits, particularly in small and medium quantities, a pre-fabricated silicon wafer is used, distinguished by a multiplicity of P and N (or N and P) structures, i.e. a structure formed by a multiplicity of impurity-doped regions each of which constitutes, for example, a P-type impurity region present in an N-type impurity region or vice versa and which impurity-doped regions are connected with contact surfaces through a silicon dioxide layer and an electrically conductive aluminium film which is placed on top of the silicon dioxide layer and forms electrical connections between preselected ones of the said P and N structures or impurity-doped regions. The connection between the contact surfaces and the aluminium film occurs through so-called contact windows in the silicon dioxide layer which are arranged more or less regularly, and are visible in the aluminium film, and whose area forms a complete or partial conductive link (a so-called ohmic contact) with the contact surface.
It is well-known that the specialist, making use of electrical connections between the individual contact surfaces (in the XY plane), can create logical or linear circuits.
The required electrical connections are produced by applying well-known photo-etching techniques, which require the use of a relatively expensive photomask.
This situation is further aggravated by the fact that such expensive photomask must be specially and separately manufactured for each specific application or photo-etching operation.